1. Field
The described embodiments relate to techniques for controlling the temperature of flat-panel displays. More specifically, the described embodiments relate to techniques for reducing the absolute temperature and temperature gradients in flat-panel displays in portable electronic devices.
2. Related Art
Flat-panel displays are typically lighter, thinner and consume less power than traditional displays, such as cathode ray tubes. As a consequence, flat-panel displays are widely used in portable electronic devices.
Many flat-panel displays are active-matrix addressed displays in which two-dimensional arrays of light valves are used to modulate light from a light source. For example, in liquid crystal displays, a liquid crystal is sandwiched between two electrodes. By applying an electrical voltage between the electrodes, the light diffusing or polarizing properties of the liquid crystal can be modified so that light is transmitted or blocked. The spatial modulation of the light across a two-dimensional array creates an image.
However, the light sources (such as light-emitting diodes) and electronics used to illuminate and apply electrical signals to liquid crystal displays generate heat. This heat can cause temperature changes in a liquid crystal display. Because the optical properties of liquid crystals are often a function of temperature, these temperature changes can cause color changes and other visual artifacts that can degrade the quality of the displayed image.